[asterisk-users] Require a Type 102 milliwatt number

[Lyle Giese]

Tilghman Lesher wrote:
> On Tuesday 27 May 2008 17:17:41 John Novack wrote:
>   
>> Jared Smith wrote:
>>     
>>> On Tue, 2008-05-27 at 16:42 -0400, Dean Collins wrote:
>>>       
>>>> How do you get asterisk to send a 102 Milliwatt signal?
>>>>         
>>> The Milliwatt() dialplan application sends a 1000 Hz tone.  (I'm still
>>> waiting for the developers to agree that it should be 1004 Hz, but
>>> that's another issue.)
>>>       
>> 1004Hz has been the Telco standard for many a year.
>>     
>
> You can already do that with simple dialplan:
>
> exten => 8114,1,Answer
> exten => 8114,n,PlayTones(1004/1000)
> exten => 8114,n,Wait(300)
>
>   
>> Just another example of why the developers need to go to a basic Telco
>> school before reinventing the wheel ( sometimes incorrectly )
>>     
>
> There is no need to insult the developers.  Yes, there's a reason why the
> typical milliwatt application is not exactly 1000Hz.  I think we've actually
> left the Milliwatt application the way that it is for historical reasons,
> ironically enough.
>
>   
The sampling rate on a T1 for a DS0 is 8kHz and 1kHz is a harmonic of
8kHz and harmonic distortion can cause significant measurement errors.
So early on engineers tuned the test frequency to be slightly off to
keep harmonic distortion to a minimum when taking loss measurements.

Lyle Giese

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